This large multidisciplinary program contains seven separate projects devoted to several aspects of nervous system development. Four of the projects are primarily concerned with normal and abnormal glial development, two with cytoskeletal interactions, and one with neutral glycosphingolipids. The major goals are: to further define normal oligodendrocyte lineage and differentiation in vitro; to determine whether acetylCoA- carboxylase is enriched in oligodendroglia and is affected in diabetic rats; to investigate the glial content of glucose-6- phosphate dehydrogenase; to explore oligodendroglial differentiation and development in the myelin-deficient rat mutant, both in vivo and in vitro; to define the origin of astrocytes cultured from mature brain; to explore the nature and biochemistry of reactive astrocytes; to define the composition and enzymology of a large class of reactive astrocytes; to define the composition and enzymology of a large class of neutral glycosphingolipids in whole brain, cell cultures, separate cells, growth cones and sensory neurons; to characterized the immunologic modulation of oligodendrocytes and determine the expression of MHC antigens on these cells; to determine how phosphorylation of neurofilaments affects their assembly, and to explore the nature and biochemistry of interactions of cytoskeletal elements in normal and perturbed nervous system. The methodology includes enzyme purification, preparation of polyvalent and monoclonal antibodies, enzyme assays, immunocytochemistry, tissue culture, (3H)-thymidine labeling, autoradiography, protein phosphorylation, ultrastructure, cytoskeleton purification, protein purification by column chromatography and FPLC, gel electrophoresis, fluorography, filament assembly, microtubule assembly, morphometry, lipid separation and analysis, GLC, TLC, subcellular fractionation, and immunoblotting. The long range goals of this program are to provide detailed information on some well-define processes of differentiation and development of the nervous system, so that we may better understand how they are perturbed by genetic or environmental influences.